Underpad



Feb i8, i969 M. NIMOY 3,427,670

UNDERPAD Filed June 22, 196'? Sheet of 2 Tll. (PRO ART) l INVENTOR.MYV/N /V/Mo Y.

BY M l k ATTO NEY M. NIMOY UNDERPAD Feb. 18, i969 Filed June 22, 1967INVENTOR //'/f y//v /V//wo Y NEON United States Patent O 1 ClaimABSTRACT F THE DISCLOSURE This invention is with respect to alaunderableunderpad having a water repellent layer where fabric bunchingdue to differential in shrinkage between fabric layers and theentrapment of internal pilling in such pad have been obviated.

Underpads are designed, in the main, to function to protect the bed,i.e. blankets, sheets and mattress, from soiling due to body exudates,e.g. urine. Many materials have been utilized for this purpose, however,while the need for a pad that can be laundered and reused over a longduration is established, several disadvantages have appeared which haveseverely hampered the use of such an item to date.

These and other disadvantages are overcome by the instant inventionwhich provides a launderable underpad comprising a plurality of plies ofydiaper fabric superimposed in facewise engagement and a sheet offlexible water impervious material secured in facewise engagement to atleast one ply of said fabric, said fabric being present in sufficientexcess to satisfy the shrinkage differential between said waterimpervious sheet, and said underpad having spec-ifically locatedopenings for the removal of fiber pills.

The water impervious repellent layer of the launderable underpad of thisinvention must be flexible and must remain flexible through repeatedlaundering and drying. It must not stiften and crack to provide liquidstrike through areas and it must not provide the discomfort factor thatis defined by a stiffened or stiff layer or ply in the underpad.

The repellent ply or layer of this invention comprises a layer offlexible water impervious material which does not lose the major portionof its flexibility after undergoing repeated laundering and dryingcycles and a layer of textile backing material secured to this waterimpervious material. The water impervious material must be resistant toattack by laundry soaps, detergents, bleaches and other such materialsor chemicals used in the normalwashing or laundering of such pads. Itmust be nonirritating to the skin of the average person under reasonableconditions and it must not present a disagreeable odor.

Since normal laundering takes place in the presence of water heated to atemperature range between about 170 F. and about 200 F., and normaldrying takes place at temperatures ranging up to about 350 F., the waterimpervious repellent layer must retain the major portion of its flexlife through at least about one hundred each of the laundering and-drying cycles as defined herein.

Preferably the material used in, or for, this repellent layer is butylrubber since it easily satisfies all of the above requirements, althoughacrylic polymers and silicone rubbers and other such materials can alsobe utilized. Also, the repellent layer may consist, in total, of a sheetof the above defined materials, however, present day plastics do notcombine desirable hand and strength. For example, if any of the presentday plastics are made into sheet form thin enough to use, they will betoo weak to withstand tearing, while if they are thickened to providesufficient tear strength, flexibility and hand are often ice sacrificedand the economics involved become prohibitive. Additionally, washing anddrying machines are loaded on a weight basis and the economics of suchoperations are sacrificed with the use of heavier underpads. Thus therepellent plastic film is usually secured to a textile sheeting fabrichaving a count of at least about 48 x 44 since a more open fabric wouldnot provide good adherence and the shrinkage of the fabric would be suchas to cause problems of separation. Preferably this textile sheeting isof high count, however, the economics involved provide a commercialceiling.

The repellent plastic sheeting must not shrink during repeatedlaunderings such as to exhibit greater than about a 3% total loss ineither the length or width of the pad. A greater shrinkage in eitherdirection would establish separation between the backing sheet which issecured to the repellent film. This would also place a severe strain onthe stitching holding the plastic film in place in the underpad togetherwith resultant fabric bunching along the. edges of the underpad.

As used herein laundry cycle and laundering shall be synonymous andshall be defined with respect to a Prosperity Junior Washer, Model 20,Serial No. 1054, utilizing a normal wash load of 20 pounds of underpadswhere a first washing shall initiate the cycle and shall comprise addingl2 gallons of water at about 160 F. to a charge consisting of 15 gramsof White Ribbon Chip Soap sold by Hampden Color and Chemical Company,cc. of Chlorox chlorine bleach, l5 grams of soda ash and 8 grams ofCalgon water conditioner, and agitating for fifteen minutes. This isfollowed by a second washing which is a repeat of the first washingcycle except that the charge consists of 8 grams of White Ribbon ChipSoap, 8 grams of soda ash and 2 grams of Calgon water conditioner. Thissecond washing cycle is followed by four, five minute rinse cycles wherethe first two shall each utilize 24 gallons of water at F. and the lasttwo shall each utilize 24 gallons of unheated normal tap water, exceptthat with the last rinse there shall be added 100 cc. of Velva-Soft G,sold by Armour & Company and 2 grams of zinc silicon uoride. The cycletimer for automatic control is Formatrol, Model FA 2093, No. 4777.

As used herein drying and drying cyclef shall be synonymous and shallconsist of drying such normal wash loads of underpads in a Huebsch GasDryer, Ser. No.. 67,093, at 200 F. for twenty minutes.

The absorbent fabric used in the underpad of this invention should besoft and is preferably gauze diaper fabric. This fabric must be presentin an amount sufficient to satisfy the minimum absorbency required ofsuch an underpad, yet present in an amount sufiicient to preventoverflow of fiuids from the face of the underpad.

Diaper fabric is usually low count woven cotton fabric. It ischaracterized by a woven construction of warp and filling yarns whereinthe warp yarns extend substantially parallel to the length of the fabricand the fill yarns extend in the widthwise direction of the fabric,which is usually produced in continuous length. This fabric may have aplain, twill, Sateen, satin, birdseye, etc., weave, all of which arefamiliar to those skilled in the art.

Because of techniques of spinning, weaving and finishing used in themanufacture of cotton fabrics, the fabric as a whole is usually undertension due, for example, to the twist of the yarn, the weave, etc.;therefore, it must be appreciated that it will be stretched to a greateror lesser extent. Washing, or laundering of the fabric, will quitenaturally relieve the tension and with the internal tension relieved thefabric will, on drying, change in dimension since the individual yarnswill assume positions closer to the adjacent yarn member of the fabricthroughout, and the interstces between yarn will be lessenedappreciably.

Thus, the original unit area of the fabric is diminished. It

is the result of this diminution of fabric and the effect it produces inthe underpad that is overcome by this invention.

The fabric used in underpads of this invention is that which isconsidered and known by the art as gauze diaper fabric, however, anyabsorbent fabric ordinarily used in diapers can be substituted therefor.Thus, within this definition and considering the then appropriate yarnsizes, the fabric will only be so open as is acceptable for diaperfabric measured in terms of acceptable absorbency, strength, softness orlack of roughness, corrugation and abrasion resistance.

The invention will be more readily understood by refence to theaccompanying drawings wherein:

FIG. 1 is a planar view of a prior art lauderable underpad with acutaway portion showing its construction,

FIG. 2 is the underpad of FIG. 1 shown in a state representative of theactual physical state and appearance that it would present after havingundergone about twenty-five laundering and twenty-five complementarydrying cycles,

FIG. 3 is a cross section taken along line 3-3 of FIG. 2,

FIGS. 4 and 5 are planar views of embodiments of diapers of thisinvention, and

FIG. 6 is a cross section taken along line 6-6 of FIG. 5.

After the pad of FIG. 1 has been subjected to about ten each of suchlaundering and drying cycles, the vinyl plastic repellent layer 4 hasundergone about a 1 to 2% reduction in both the lengthwise and widthwisedirections while the layers of gauze fabric 2, 3 and 5 have undergoneabout a 12% to 15% over-all reduction in each such direction. As aresult, the physical appearance of the pad 1 is similar to that depictedvia FIG. 2 except that the fabric failure depicted Iby holes 9 infabrics 2 and 3 of the pad have ordinarily not yet occurred. However,the terminal edges 7 of the pad 1 have begun to curl up due to thedifferential in shrinkage that exists between the shrinkage of repellentlayer 4 and that of the fabrics 2, 3 and 4. Additionally, corrugation orinternal bunching of the repellent layer 4 is evidenced by corrugationin the pad 1.

After about twenty-five washing and drying cycles the pad 1 appearssubstantially as it is depicted in FIG. 2 and is shown by the enlargedcross section which is FIG. 3 and is taken along line 3-3 of FIG. 2. Thevinyl plastic repellent layer 4 has begun to stilen and cracks 8 beginto appear. The areas of corrugation 10, whether or not they areaccompanied by cracks 8 and the upturned edges defining so many of thesecracks, receive the brunt of the abrasive wear that the pad 1 receives.This localized abrasive wear causes the premature fabric failure,represented by holes 9, resulting in the exposure of the stitfenedplastic repellent layer 4. The cracks 8 of the stiffened plastic layer 4present sharp edges, as do the upturned exposed terminal edges 7 of thestiffened plastic layer 4. These edges act in a fashion suggestive of aknife blade, to scratch and cut the exposed skin of one lying on the pad1 and to cause damage to articles of clothing or bedding with which theycome into contact.

The areas of corrugation 10 caused by the localized bunching of therepellent layer 4 due to the greater shrinkage in the gauze diaperfabrics 2, 3 and 5 which confines and lessens the over-all area of therepellent layer 4, provide many areas `of localized discomfort since theoriginal flat surface of the pad is destroyed. Additionally, repeateduse and laundering of the pad 1, which is defined by multi-ply cloth andwhere there is substantial freedom between the plies of cloth, isusually attended by fabric pilling. This is due to the natural abrasionacting on the surface of the cloth of layers 2 and 3 during washing,drying and every day use, etc. whereby fiber pills are detached from thematerial and are trapped between the absorbent layers of the pad and thewater repellent layer.

These fiber pills gather and, largely through the action of the forcesattending the aforementioned actions of washing, drying and normal use,form into small balls 11 which also provide points of discomfort to theuser, and which are potential sources of skin irritation. These fabricballs 11 also provide points of high spotting and resultant prematurewear.

The stiffening of the vinyl plastic of the repellent sheet 4 is causedby the leaching out of the plasticizer during repeated laundering anddrying. The resulting loss of exibility causes the cracks which destroythe functionality of the repellent layer 4. Many other plastics orsynthetic sheet materials which have good fiex life built into them bythe use of a plasticizer, undergo similar results when they are exposedto repeated laundering and drying cycles.

The liquid repellent layer of this invention must consist of a materialwhich is flexible and retains sufiicient of its flexibility afterundergoing at least about one hundred each of the laundering and dryingcycles defined herein, to exhibit good flexibility and no cracking. Itshould also have good dimensional stability under these same conditionssuch that its shrinkage is no more than about 3% in either thelengthwise or the widthwise directions and is must be a material whichis not a skin irritant. Butyl rubber is the preferred member of theseveral materials that satisfy these requirements. Other such materialsare acrylic polymers and silicone rubber.

As discussed earlier, the repellent layer of this invention may be aplastic sheet in, and of, itself in which case a ply of backing fabricmust be superimposed in facewise engagement with each of its faces, orit may be coated onto a fabric such as ordinary sheeting material, toprovide a coated fabric layer which is water repellent.

FIG. 4 is a planar view of one embodiment of an absorbent pad of thisinvention. The absorbent pad 20 consists of two plies 21 and 22 of gauzediaper fabric and a backing sheet 23 which is also the water repellentply of the pad 20. The backing sheet 23 is constructed of two plies, oneply of 68 x 72 crib sheeting material shown in cutaway and shown withone corner upturned to expose the outer surface or face 25. This backingply 23 has its inner surface 24, i.e. the surface in facewise engagementwith the inner ply 22 of gauze diaper fabric, coated with a layer ofbutyl 'rubber which has been calendered onto the sheeting. The exposedfacing surface 25 of the repellent layer 23 presents lthe soft surfaceof the crib sheeting material and is the surface that forms the backingface of the pad `20.

The butyl rubber coating on the backing ply 23 is applied in an amountsufficient to insure impermeability to urine and other such liquidswhich it is meant to bar. The butyl coating is thus present in an amountof preferably 7 to 8 ounces per square yard to provide a substantiallyuniform coating thickness throughout this surface of the sheetingmaterial, of at least about 0.008 inch. This ensures that tufts orerrant fiber protrusions which might provide sites of liquid seepage areeliminated.

The gauze plies 21 and 22 are secured together by overedge stitching 26while the backing ply 23 is sewn to the composite of fabric by safetystitching 27. Openings 28 and 29 between the fabrics 21 and 22 and thebacking ply 23 are strategically located at diagonally opposed edges toprovide maximum ensurance that pills formed during use, etc. can escape.This then eliminates the high spotting that has caused localizeddiscomfort sites and has provided sources of skin irritation toincontinent patients and has provided spots of premature fabric failure.

Note that the composite of plies 21 and 22 is present in excess as isshown by the fabric bunching 30 in the pad 20 of FIG. 4. This isconstructed into the pad 20 to compensate for the differential inover-all shrinkage between the fabric plies 21 and 22 and that of thebacking ply 23.

The backing ply 23 will undergo about a 2% lengthwise and widthwiseshrinkage during repeated launderings, while the gauze plies 21 and 22will each experience about a 12% shrinkage in the same directions. Theshrinkage differential is thus about total in any one given dimension.To preclude corrugation in the pad 20, this 10% shrinkage differentialis actually determined with respect to the dimensions of the diapercloth utilized in plies 21 and 22, and the pad 20 is constructed such asto readily accept this shrinkage differential and to thus preclude theaforediscussed corrugation phenomena which establishes localized sitesof discomfort and premature wear in an underpad. For example, if theoriginal underpaid (unwashed) is to be thirty-six inches long, a fourinch excess in the length of each gauze ply 21 and 22 would be provided.The same procedureis followed with res-pect to the width of the underpadwhich is normally twenty-four inches and thus has about two and one-halfinches provided. This excess material is constructed into the underpadby differential feed sewing.

The unwashed underpad of this invention will thus present an apparentsurplusage of diaper fabric, or other such absorbent fabric, representedby the excess material constructed into the pad to overcome theshrinkage differential in the materials of the pad; however, about 75%to 80% of the shrinkage in both the backing ply 23 and the `ganz/e plies21 and 22 does take place in the first laundering and drying cycle, withonly about 2% to about 5% residual shrinkage remaining in the materialsafter the first four or five such launderings and dryings. Thus theexcess material is soon dissipated. FIG. 5 is presented to depict theunderpad of FIG. 4 after about fifty each laundering and drying cycles.Note that no corrugation, high spotting, holes in the fabric or cracksin the backing ply do appear.

Fabric pills are substantially eliminated by providing the twodiagonally situated openings 28 and 29. The openings are about fourinches in length in the periphery of the pad 20 (which is a 36 x 24 inchpad) and provide free access to the area Within the underpad 20.Surprisingly, the pills created by Wear, laundering and drying areeliminated automatically during the washing or drying cycles throughthese openings 28 and 29.

FIG. 6 is a cross section taken through 5 5 of FIG. 5 and depicts thenature of the openings 28 along with the fiat nature of the underpaditself. There is no corrugation, pilling or cracking present.

While the instant invention is designed to function as an underpad, itcould well function as a diaper.

The instant invention has been described in connection 'with itspreferred embodiments, but many modifications thereof are easilyincluded without departing from the inventive concept which is limitedonly by the scope of the appended claim.

What is claimed is:

1. A launderable underpad comprising a plurality of plies of diaperfabric superimposed in facewise engagement and a sheet of flexible waterimpervious material secured in facewise engagement to at least one plyof said fabric, said fabric being present in sufficient excess tosatisfy the shrinkage differential between said lwater impervious sheetand said underpad having specifically located openings for removal offiber pills.

References Cited UNITED STATES PATENTS 2,685,290 8/ 1954 IOBrien 12S-2872,803,836 8/1957 Hunsicker 5--334 2,963,715 12/1960 Young 5-354 X3,150,663 9/ 1964 Combs 128-287 3,316,566 5/ 1967 Long 5-334 CASMIR A.NUNBERG, Primary Examiner.

U.S. Cl. X.R.

